Bolt on oil filler cap and breather?

I just bought a set of nice Motorsport SVO aluminum valve covers off ebay. They are new in the box. Took a while to find some that were new.



I want to have the new ones Nitoplated (the ceramic header coating) and then fill in the lettering with paint that matches the car. I currently have the new version that say Ford Racing, but I like these better.

They have knockouts for holes for the typical rubber grommet/breather. I want to add a bolt in oil fill cap to one and either a bolt in breather or AN bulkhead to the other. I run an electric vac pump just to pull any moisture out and need to attach a hose to the breather or fitting.

What are some choices as far as bolt in stuff? These are too nice to weld on. To be totally legal for IHRA/NHRA I have to have a positive attachment. Just a rubber grommet is not legal for the ET's I run.

I have found these. They look nice, but just wanted to see if anyone had any other ideas.
http://www.lpwracing.com/p_billet.asp